The aim in imaging using an X-ray machine, e.g. using a computer tomograph, which has an X-ray system with an X-ray source and an X-ray detector, is to make the detection area of the X-ray detector which is available for providing images as large as possible in order to be able to scan entire organs, such as the heart, of a patient in one pass of the X-ray system around the patient, for example. Such an X-ray detector, also called area detector, is normally designed from a multiplicity of detector modules which are lined up in two dimensions.
By way of example, each detector module has a scintillator array and a photodiode array which are oriented relative to one another and which form the detector elements of the detector module. The elements of the scintillator array convert X-ray radiation hitting them into visible light, which is converted into electrical signals by the downstream photodiodes of the photodiode array. A particular problem found with the design of an area detector is the electrical contact for the photodiodes of the detector modules.
In an X-ray detector of conventional design, in which individual detector modules are arranged successively on an arc of a circle, signal-processing electronics can be arranged at the side or a cable used to make contact with the photodiodes of a module can be routed away at the side to a printed circuit board having signal-processing electronics, as can be found in US 2005/0029463 A1, this design is no longer possible for an area detector, since the two-dimensional arrangement of the detector modules means that there is no longer any free space at the sides. It should also be noted in this context that the signal-processing electronics for the measurement signals delivered by the detector elements of the detector modules, which electronics need to be arranged as close as possible to the detector elements for measurement reasons, have an area requirement which may be two to four times greater than the detection area of an actual detector module. For this reason, it appears necessary for the detector module with the signal-processing electronics to be of vertical design.
U.S. Pat. No. 6,396,898 B1 describes the design of an area detector which has a plurality of lined-up detector modules which each comprise an “element block”. The element blocks in a detector are of vertical design, i.e. the components of an element block, comprising scintillators, photodiodes, a substrate with signal-processing electronics and a module baseplate, are arranged vertically above one another.
With such a vertical design for a detector module, it is also necessary to ensure good heat dissipation, since otherwise the considerable heat generation during operation of the signal-processing electronics can cause damage to the electronics.